You'll have no problems focusing with the Nikon 85mm f1.8. I use the 3X viewfinder magnification but you may manage without. Similar for the 105mm but for longer lenses (I use 180mm f2.8) I don't use viewfinder magnification and get sharp shots handheld (seated with elbows on a chairback), at 1/30th - how I manage that I don't know considering it has equiv FL of 270mm! Anyway it shows what is possible with third party lenses.

Vic

-- hide signature --

The sky is full of holes that let the rain get in, the holes are very small - that's why the rain is thin.Spike Milligan